The most appropriate management is to perform a stool antigen assay for Helicobacter pylori infection. This patient has iron deficiency anemia. Iron deficiency is a common problem because of the precarious balance between iron intake and use. Women of reproductive age may lose enough iron through normal menstrual blood loss to become iron deficient in the absence of uterine or gastrointestinal disease. Iron malabsorption is a relatively uncommon cause of iron deficiency but should be considered when no other cause of iron deficiency is apparent and particularly when the deficiency is refractory to adequate iron replacement therapy. It is usually caused by generalized malabsorption conditions such as celiac disease, achlorhydria secondary to atrophic gastritis or proton pump inhibitor therapy, or, occasionally, H. pylori infection. This patient's history of chronic dyspepsia and refractoriness to oral iron therapy suggest the possibility of H. pylori infection. H. pylori infection is endemic in many developing countries. Patients treated for underlying H. pylori infection may have improved iron absorption, making oral iron replacement an effective treatment.

Although ascorbic acid can facilitate iron absorption, no convincing data suggest the addition of this agent is worth the increase in cost or gastrointestinal toxicity.

Celiac disease is an immunologic response to dietary gliadins in patients genetically at risk as deemed by the presence of HLA-DQ2 or HLA-DQ8. The typical features of celiac disease are diarrhea, bloating, and weight loss; it is diagnosed mainly in whites of northern European ancestry and would be an unusual cause of refractory iron deficiency anemia in a woman of African descent with dyspepsia. Antigliadin assays have poor sensitivity and specificity and a high false-positive rate, so they are not recommended for diagnosing celiac disease.

Iron deficiency is most easily treated with oral iron salts. Oral ferrous sulfate is the least expensive preparation. Each 325-mg tablet of ferrous sulfate contains 66 mg of iron, 1% to 2% of which is absorbed. Although other oral iron salts such as ferrous gluconate or ferrous fumarate are available, none of these have proved superior to ferrous sulfate in tolerability or efficacy.